WGS to determine the extent of Clostridioides difficile transmission in a high incidence setting in North Wales in 2015.
Eyre DW., Shaw R., Adams H., Cooper T., Crook DW., Griffin R-M., Mannion P., Morgan M., Morris T., Perry M., Jones S., Peto TEA., Sutton J., Walker AS., Williams D., Craine N.
OBJECTIVES: Rates of Clostridioides (Clostridium) difficile infection (CDI) are higher in North Wales than elsewhere in the UK. We used WGS to investigate if this is due to increased healthcare-associated transmission from other cases. METHODS: Healthcare and community C. difficile isolates from patients across North Wales (February-July 2015) from glutamate dehydrogenase (GDH)-positive faecal samples underwent WGS. Data from patient records, hospital management systems and national antimicrobial use surveillance were used. RESULTS: Of the 499 GDH-positive samples, 338 (68%) were sequenced and 299 distinct infections/colonizations were identified, 229/299 (77%) with toxin genes. Only 39/229 (17%) toxigenic isolates were related within ≤2 SNPs to ≥1 infections/colonizations from a previously sampled patient, i.e. demonstrated evidence of possible transmission. Independent predictors of possible transmission included healthcare exposure in the last 12 weeks (P = 0.002, with rates varying by hospital), infection with MLST types ST-1 (ribotype 027) and ST-11 (predominantly ribotype 078) compared with all other toxigenic STs (P